Referring to FIG. 5, a conventional tool-holding apparatus 60 includes a board 62 and two rows of holders 64 formed on the board 62. Referring to FIG. 6, each holder 64 is formed on a plain area 63 of the board 62. A concave area 65 is located next to each plain area 63. Each holder 64 includes a first section 66 extending from each plain area 63, a second section 68 extending from the first section 66, a third section 70 extending from the second section 68 and a stop 72 extending from the first section 66 opposite to the second section 68. A gap 74 exists between the third section 70 of each holder 64 and each plain area 63 of the board 62. A gap 76 exists between the first section 66 of each holder 64 and the third section 70 of the next holder 64. A spanner 100 is put in the gap 76 so that the spanner 100 presses the third section 70 towards the plain area 63. Hence, the spanner 100 is restrained by the stop 72 and the third section 70. However, the gap 76 is too narrow to encompass various sizes of spanners. Moreover, the gap 74 is too narrow to allow adequate pivotal movement of the third section 70 caused by insertion of the spanner 100. That is, the third section 70 is squeezed between the plain area 63 and the spanner 100. Thus, the third section 70 is deformed and might therefore be damaged. When subject to vibration, the spanner 100 can easily slide on and past the stop 72 and fail from the tool-holding apparatus 60.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.